Minimizing the downtime of a machine tool in a production environment is critical to the success of a manufacturing facility. Historically, one major contributor to such downtime was the time needed to change damaged or worn out cutting tools used by the machine tool. A cutting tool is held by a toolholder, which is typically mounted within a tool support member secured to a machine tool. When the cutting tool must be replaced, the entire toolholder with the cutting tool is removed from the spindle. A number of couplings are designed to permit quick connecting and disconnecting of the toolholder to and from the spindle to expedite the tool changing process. One such device is described in U.S. Pat. No. 4,736,659 entitled “Toolholder assembly for Holding a Toolholder Shank.” This patent is co-owned by the Assignee of the present application and is hereby incorporated by reference. The toolholder assembly described in that patent utilizes two locking balls which are urged radially outwardly within a tool support member to engage apertures on the shank of a toolholder. While this arrangement is efficient and permits the toolholder to be removed or secured to a tool support member in a short amount of time, the design of this arrangement may limit its application to toolholders having a width of one inch or less. Since many industrial applications require the use of a cutting tool which must be mounted on a much smaller toolholder, a need exists for a quick change toolholder system for toolholders which may be designed having a width of less than one inch.
Such a system must not only have a compact design, but furthermore, provide quick connecting and disconnecting of the toolholder from the toolholder support member in an efficient manner that makes it practical for use by a machine tool operator.
An example of a suitable compact design is described in U.S. Pat. Nos. 6,270,293 and 6,415,696, incorporated herein by reference. The design described therein includes square shank clamping components, a lock screw and a lock centering nut retained in a bore and pocket, respectively. The components fit into the tool support member with a slight clearance. When the toolholder is clamped into the tool support member it is preferred that the toolholder is radially aligned with the central radial axis of the tool support member. However, it will be appreciated that due to slight manufacturing tolerances between the various components and the cutting load experienced by the toolholder the radial location of the toolholder with respect to the centerline of the tool support member may vary.
The present invention is an improved quick change tooling system that result in improved radial location of the toolholder with respect to the tool support member.